1. Field of the Invention
The present invention relates to a wireless communication system, and more particularly to an Access Point (AP) for use in a wireless LAN system.
2. Description of the Related Art
Recently, the IEEE 802.11a/g has been established as the latest Wireless Local Area Network (WLAN) technology standard, in regard to high-speed wireless equipment capable of supporting a transfer rate of 54 Mbps that has recently been introduced to the market. There is increasing user demand for networking technologies of household appliances contained in a home network, which has been proposed as a major application of WLAN technologies. Many developers have conducted intensive research into WLAN technologies in an attempt to increase wireless speed and data throughput, and currently attempts are under way to raise wireless link speeds to a predetermined speed of 200 Mbps using Multiple Input Multiple Output (MIMO) technology of the IEEE 802.11 TGb standardization group. The Medium Access Control (MAC) layer applies a resource request scheme to a random access scheme in order to increase efficiency of radio resources, such that the MAC output can be increased by 80%.
FIG. 1 is a conceptual diagram illustrating a conventional wireless LAN environment. Referring to FIG. 1, a plurality of APs (Access Points) 11, 13, 15, and 17 form individual cells 11a, 13a, 15a, and 17a, respectively. In this case, although the APs 13 and 15 use different channels (i.e. channel #11 and channel #1), an unexpected overlapping portion occurs, resulting in signal interference. Furthermore, when APs 15 and 17 use the same channel (e.g. channel #1), serious interference may be encountered in a boundary area.
In order to implement a wireless home LAN network system, inter-cell interference generated during cell planning and a performance anomaly phenomenon must be removed. However, if a multi-cell AP environment is implemented using a conventional IEEE 802.11 standard, an inter-cell frequency inference phenomenon and a performance anomaly generated at a cell edge are generated, resulting in a reduced output level and increased transmission delays.
The cell-planning scheme for constructing conventional wireless home LAN network systems may have difficulty in arranging cells, and may unexpectedly encounter coverage holes. A mobile terminal is unable to receive radio signals in the coverage hole, resulting in a communication failure. When a terminal desires to move from a current access AP to another AP in the wireless home LAN network, probing, re-association, and authentication functions must be applied to the AP, resulting in considerably longer handoff latency.
The AP covers a large-sized cell area in the conventional home LAN scheme. Therefore, radio signals from the AP may go outside of a home or building area if a home LAN or building LAN environment is so constructed, allowing communication packets between an AP and an authorized terminal to be received by an unauthorized terminal, resulting in a security problem.